The fields of the invention are methods and apparatus for sampling particles on surfaces to allow for the detection of hazardous particles. The prompt detection of hazardous particles is advantageous in a number of situations. For example, terrorists and others may seek to destroy commercial aircraft by placing explosives into luggage and other containers taken onto the aircraft, and subsequently detonating the explosives. One approach to avoiding such attacks is to screen all persons and containers before they are onboard the aircraft. If a person has been handling explosives, then particles of the explosive may be present on the person's hands and clothing. If there is an explosive in a piece of luggage or other container, then explosive particles may be present on the exterior of piece of luggage or other container. Current detection methods include wiping the exterior of luggage and other containers with a swab, and then inserting the swab into an analyzer which is adapted to detect any explosive particles on the swab. Current detection methods also include placing a person in an air booth which directs blasts of air at the person, and collects the deflected blasts of air, and delivers the deflected air to an analyzer which is adapted to detect any explosive particles in the deflected air.
However, there are limitations on current detection methods and apparatus. The current methods and apparatus may involve a significant delay and inconvenience, from the perception of passengers who are seeking to board commercial aircraft. In addition, the detection capability of current detection methods and apparatus leaves room for improvement.
In the fields of inventions, the particles of interest may be solids, or semi-solids, or small droplets of liquid. These particles of interest may be hazardous, or indicative of hazardous materials, or may be disguised particles. A disguised particle may be a hazardous substance that is coated with a non-hazardous material in an attempt to avoid detection, and in such circumstance the hazardous material may be referred to as the payload.
In the fields of invention, the hazardous particles may be explosives, poisons, toxins, biological materials, radioactive substances and other weapons of mass destruction. These explosives may fall into different categories. For example, nitroglycerine may be regarded as an ester, TNT may be regarded as an aromatic, and RDX may be regarded as a nitramine. There are also peroxide explosives, such as HMTD, TATP, DADP and TMDD.
There are a number of known methods and apparatus to analyze particles, and determine whether the particles are hazardous materials. These include infrared (IR) spectroscopy, and Raman spectroscopy, as well as others.